METHOD FOR RELINING A BRANCH CONDUIT OF A MAIN CONDUIT

Abstract: The invention relates to a method for relining an underground branch conduit (10) of an underground main conduit (11) by a relining pipe (14) in the form of a radially stiff double-walled pipe with a corrugated outer wall (14A) and a smooth elastic inner wall (14B) being inserted by means of a traction rope (22), a draw shoe (20) and a pressure plate (25). A stop element (27) is provided on the traction rope (22), which can be pressed against the draw shoe by the motion of the traction rope in relation to the draw shoe.

Description: METHOD FOR RELINING A BRANCH CONDUIT OF A MAIN CONDUIT The invention relates to a method for relining an underground branch conduit of an underground main conduit by a relining pipe being inserted into the branch conduit and brought to tight engagement with the main conduit. Damaged or leaky pipelines can be relined in several ways but especially preferred are methods in which a re¬ lining pipe is inserted into the damaged pipeline. The advantage of these methods is that extensive excavation and digging work can be avoided since the work mainly can be performed from existing manholes. Prolonged interruptions in industrial areas as well as traffic diversions can thereby be avoided. One method for relining pipeline systems with branch conduits comprises relining first of the main conduit and then of the branch conduit a tight connection then being accomplished between the main conduit and the branch conduit . According to US-A-4 029 428 relining of the branch conduit is accomplished after relining of the main conduit, by the relining pipe being pushed into the branch conduit from the upstream end thereof, i.e. the end opposite to the end connected to the main conduit. Then a tight connection is formed between the relined main conduit and the relined branch conduit by introduction of polyurethane foam via the branch conduit, which is allowed to set in the junction area, and a connection passage is cut between the main conduit and the branch conduit from the branch conduit at the junction site. According to GB-A-2 326 158 relining of the branch conduit is accomplished by a relining pipe being pushed into the branch conduit from the upstream end thereof a sealing element a being provided at the front end of the relining pipe. The sealing element is pushed into the main FIG 1 is a fragmentary perspective view of a conven¬ tional pipeline system with a main conduit and a branch conduit connected to it, FIG 2 is an axial cross sectional view of a main conduit with a branch conduit connected to it shown in plan view, FIG 3 is a fragmentary plan view of relining pipes for a main conduit and a branch conduit, and FIG 4 is an axial cross sectional view of the re- lining pipe for a branch conduit with a draw shoe, a traction rope and a pressure plate. FIG 1 shows a branch conduit (service pipe) 10 for a house. The conduit is located in the ground outside the house and one end thereof is connected to an underground main conduit 11. Assuming that the pipeline system, including the main conduit 11 and one or more branch conduits 10, need to be renewed, the connections of the branch conduits with the main conduit are first mapped, which can be made in a known manner, for example by the introduction of a marker through the branch conduit up to the place where it opens into the main conduit. The marker can be detected by a robot which is introduced into the main conduit or by scanning the main conduit by means of a camera introduced into it. The dis- tances to the openings of the branch conduits in the main conduit are then determined from a place on the main conduit where a manhole is available or a shaft has been provided. This measurement is combined with an angle meas¬ urement for determination of the angular position of the branch conduit opening in the main conduit. Then, a re¬ lining pipe 12 is introduced into the main conduit 11 by means of known techniques. In the present case this relining pipe is assumed to consist of a radially stiff (circumferentially stiff) double-walled pipe of weldable plastic with a smooth inner wall and a corrugated outer sealant since weldings against pipes of cement or concrete cannot be accomplished.

Claims: CLAIMS 1. Method for relining an underground branch conduit (10) of an underground main conduit (11) by introducing into the branch conduit via the main conduit a relining pipe (14) with a substantially circular cross section adapted to the branch conduit, and tightly connectiong to the main conduit on the inside thereof a flange (17) at one end of the re¬ lining pipe, c h a r a c t e r i z e d in that a radially stiff double-walled pipe with a corrugated outer wall (14A) and a smooth elastic inner wall (14B) is used as relining pipe, that a draw shoe (20) is attached to the other end of the relining pipe (14) , that a traction rope (22) is introduced through the branch conduit (10) into and through the main conduit (11) as well as through the draw shoe and the relining pipe and is secured to a pressure plate (25) in said other end of the relining pipe, and that a stop element (27) is provided on the traction rope (22) , which can be applied against the draw shoe by the motion of the traction rope in relation to the draw shoe. 2. Method as claimed in claim 1, c h a r a c ¬ t e r i z e d in that a spring (24) is connected between the pressure plate (25) and the draw shoe (20) . 3. Method as claimed in claim 1 or 2, c h a r a c - t e r i z e d in that a sealant is applied on the flange (17) for tight connection of the relining pipe (14) to the main conduit (11) . 4. Method as claimed in any of claims 1-3, c h a r a c ¬ t e r i z e d in that the flange (17) is welded to the inside of the main conduit (11) by fusing the plastic material thereof by electric heating by means of resistance wires (18) in or on the flange (17) . 5. Method as claimed in any of claims 1-4, c h a r a c - t e r i z e d in that a gasket (19) is applied between the flange (17) and the inside of the main conduit (11) .

Inventors: HUIKARI PASI TAPIO, HUIKARI, PASI, TAPIO
Applicants: HUIKARI PASI TAPIO, UPONOR INNOVATION AB, HUIKARI, PASI, TAPIO
Application year: 1994
Main classification: F16L55
IPC codes: F16L55